Add missing include.

Change-Id: I2a52d050a39e2c6dd38af868ea444278d9b6d54d
diff --git a/tests/cts/net/jni/NativeDnsJni.c b/tests/cts/net/jni/NativeDnsJni.c
index b975594..4eb3c7a 100644
--- a/tests/cts/net/jni/NativeDnsJni.c
+++ b/tests/cts/net/jni/NativeDnsJni.c
@@ -18,6 +18,7 @@
 #include <jni.h>
 #include <netdb.h>
 #include <stdio.h>
+#include <string.h>
 #include <utils/Log.h>
 
 const char *GoogleDNSIpV4Address="8.8.8.8";